1. Field of the Invention
Embodiments of the present invention relate to a battery pack management system.
2. Description of the Related Art
In recent times, compact, slim and light-weight portable electric/electronic devices including cellular phones, notebook computers and camcorders are actively developed and produced. These devices have a battery pack to be operated in any places to which a power source is not provided. Examples of the battery pack include nickel-cadmium (Ni—Cd), nickel-metal hydride (Ni-MH) and lithium (Li) batteries, in an economical aspect, which are generally rechargeable secondary batteries.
The Li batteries have, in particular, been widely employed in the latest generation of electronics devices. A Li battery may have an operation voltage of 3.6V, which is about three times the operation voltage of comparable Ni—Cd or Ni—MH batteries. The Li battery may exhibit a relatively high energy density per unit weight.
The lithium ion battery has an unstable chemical composition, in an event of over-charge, over-discharge or over-current, there are high risks of performance deterioration, leakage, heat and smoke, fire or rupture. Thus, in order to protect the lithium ion battery from the risks, the lithium ion battery requires a protection circuit. The protection circuit necessarily performs the following functions. First, the protection circuit performs a charge/discharge controlling function for protecting the battery against over-charge, over-discharge, over-current, or over-heat. Second, the protection circuit performs a fuel gauging function for measuring voltage, current or temperature and integrating accumulated capacity. Third, the protection circuit communicates with a device set in a SMBus manner with regard to information on current, voltage and temperature.
The protection circuit is referred to as a smart circuit. Battery information is obtained from the smart circuit and is supplied to a host device.
In addition, the smart circuit, including a microprocessor, constitutes a battery management system. The microprocessor includes a firmware for driving the same and performs appropriate operations adapted to various situations using a data flash that is internally or externally stored.
However, when an error is generated in the firmware or data flash, serious problems, such as fire, rupture, heating or smoke, may occur to the battery, and product stability may be ruined. In addition, manufacturers are unavoidably forced to recall products in a large scale, and even more undesirably, there is no countermeasure to come up with such a massive product recall event.